The overall objective of this research is to determine what limitations in auditory analyzing capabilities are associated with sensorineural hearing losses. Initial research concentrates on measures of frequency resolution and on measures of temporal resolution at frequency regions relative to sensitivity losses. Future research will examine frequency resolution and temporal resolution for specific etiologies regardless of region of sensitivity loss. The specific goals of this research are organized around three central themes: a) Frequency resolution and frequency-selective sensitivity losses, b) Temporal resolution and frequency-selective sensitivity losses, and c) Frequency dependence of temporal resolution and frequency-selective sensitivity losses. During this first grant year, experiments were initiated to accomplish specific goals in each of those three areas. Forward-masked tuning curves were obtained at three frequency regions from sensorineural-impaired ears with varying sensitivity losses in order to examine frequency resolution relative to regions of sensitivity loss (item 'a' above). Iso-response temporal marking curves for same-frequency masker and probe were obtained from sensorineural-impaired ears in order to examine temporal resolution relative to regions of sensitivity loss (item 'b' above). In addition, iso-response temporal masking curves were obtained from sensorineural-impaired ears for masker frequencies both above and below the probe frequency in order to examine the frequency dependence of temporal resolution relative to regions of sensitivity loss (item 'c' above). Since we are using forward masking as a tool to investigate limitations in auditory analyzing capabilities, several experiments have also been initiated to help understand the mechanisms of forward masking in both normal and abnormal hearing systems. Those experiments examine level effects, off-frequency listening, and pitch shifts with intensity.